In H.264/MPEG-4 Part 10 (ISO/IEC 14496-10) (referred to as “H.264” below) (see Non-Patent Document 1), motion-compensated prediction schemes involve blocks of 16×16, 16×8, 8×16 and 8×8 in 16×16-block units and subblocks of 8×8, 8×4, 4×8 and 4×4 in 8×8-block units.
If an 8×8 block has been selected when motion-compensated prediction is performed in 16×16, 16×8, 8×16 and 8×8 blocks, the optimum block is selected from among the subblocks.
In contribution JVT-I1049d0.doc (Non-Patent document 2) at a meeting of the JVT (Joint Video Team) performing H.264 standardization work, the following have been proposed as an evaluation measure for selecting a block in a motion-compensated prediction apparatus: SAD (Sum of Absolute Differences), which generates a cost value of difference information indicative of a difference between a moving-picture signal that is input to a moving-picture compression encoding system and a prediction signal that is output from a prediction signal generating system; and SATD (Sum of Absolute Transformed Differences), which subjects this difference information to a Hadamard transform and generates cost values for all block sizes.
In H.264 referential software (Joint Model, referred to as “JM” below) that has been developed as part of the standardization activities by the JVT, the SAD and the SATD are employed in block selection in a motion-compensated prediction apparatus. Cost values for when a block size is selected are all found based upon the SAD. Alternatively, either SAD or SATD can be selected when a motion vector, which is the input in motion compensation, is detected in units of ½ pixels or ¼ pixels.
Motion-compensated prediction selects optimum block size based upon the cost value of each block size at the time of motion vector detection.
[Non-Patent Document 1] H.264/MPEG-4 Part 10 (ISO/IEC 14496-10) Internet<URL:http://www.itu.int/rec/recomme ndation.asp?type=item&|ang=e&parent=T-REC-H.264-200305-I>
[Non-Patent Document 2] JVT-1049d0.doc Internet<ft p://standards.polycom.com/2003—09_SanDiego/>